During the past six years in which I have made use of light in the treatment of tuberculosis in its various forms I have constantly felt the need of a much more intense light than any that has yet been produced.
I believe that it is impossible to obtain a light from any source, except the sun, that is sufficiently powerful to accomplish what we desire in this direction. The electric arc light is exceedingly limited, but, with the sun as our source of supply, the amount of light is unlimited, and that which we may utilize depends wholly on the size and construction of the apparatus used to gather up the light.
The illustration shows the mirror which I now use and the relative proportion of one now nearing completion. The smaller is three feet in diameter and contains an area of seven square feet, while the larger has a diameter of ten feet and contains an area of seventy-eight square feet.